1. Field
The disclosed concept pertains generally to electrical switching apparatus and, more particularly, to such electrical switching apparatus including two poles and a single operating handle.
2. Background Information
Circuit breakers are generally old and well known in the art. Circuit breakers are used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition or a relatively high level short circuit or fault condition. In small circuit breakers, commonly referred to as miniature circuit breakers, used for residential and light commercial applications, such protection is typically provided by a thermal-magnetic trip device. This trip device includes a bimetal, which heats and bends in response to a persistent overcurrent condition. The bimetal, in turn, unlatches a spring powered operating mechanism, which opens the separable contacts of the circuit breaker to interrupt current flow in the protected power system.
Known conventional two-pole circuit breakers with dual parallel poles are believed to employ either: (a) two operating handles with a handle tie; or (b) a single operating handle over one of the poles with a shaft to actuate the other pole, but with the single operating handle not being centered and it being apparent that it is a dual pole device.
U.S. Pat. No. 6,614,334 discloses a single-pole circuit breaker including a housing, first and second circuit breaker mechanisms, a single operating handle having on and off positions, and first and second links from the operating handle to the respective first and second operating mechanisms. The first and second operating mechanisms are physically disposed in series along a longitudinal axis, which causes the circuit breaker to be relatively elongated. Two sets of separable contacts are controlled by the first and second operating mechanisms and are electrically connected in series as part of a single pole to improve the operating voltage and/or interrupting capacity of the single-pole circuit breaker. A three-pole circuit breaker can be formed by stacking three such single-pole circuit breakers in parallel, with a trip actuator member being disposed between each set of two parallel single-pole circuit breakers.
There is room for improvement in electrical switching apparatus, such as two-pole circuit breakers.